Error in service module upon first login as root

[Nathan Henrie]

Hello — I’m trying my first guix system install, on an older Acer laptop). The 
installer image seems to work fine so I had high hopes that the hardware would 
be compatible. I’m using the console-based installation which makes it easier 
to use a BTRFS root with my preferred subvolume layout.

Unfortunately, when I reboot into the installed image I try to log in with 
`root` and it flashes `Error in service module` and returns to the login 
screen. I can’t yet log in as my user as a password is not yet configured (it 
looks like the usual flow is to first log in as root and `passwd`). The machine 
doesn’t have Ethernet, and I don’t have WiFi configured yet (to try to ssh and 
debug).

Any ideas? This is the config I’m using, just a few basic packages on a BTRFS 
layout (I also tried with ext4 and had a similar result).

https://paste.debian.net/hidden/78313f40/

Many thanks for ideas on how to debug this!

Nate